ol.layer.Vector can now manage both an RTree and a Collection of features.
The new useSpatialIndex option allows to opt out of RTree management, and
the new ol.Collection type of the features option allows to opt in for
Collection management.
By using the frameState's focus, we can adjust extent and transform and
render it for the world of interest instead of wrapping it and rendering
for every visible world.
Most of our uses of source extent were cargo cult programming. The source extent was seldom and inconsistently used. Instead, layers can now be configured with an extent, and layer renderers limit rendering (and data requests) to the layer extent.
For vector sources, the `getExtent` method returns the extent of currently loaded features (this was the case before and after this change). For tile based sources, we will likely want to allow easy construction of tile grids based on an extent (this is not possible before or after this change, but could be added later).
The change in #2098 made it so a feature's geometry could be undefined. This is consistent with the return type for the getGeometry method. Where calling code needs to ensure that it has a geometry instance, it can use instanceof, goog.isDefAndNotNull(), or test for a truthy value.
This change adds a stability value to the api annotation, with
'experimental' as default value.
enum, typedef and event annotations are never exportable, but
api annotations are needed there to make them appear in the
docs.
Nested typedefs are no longer inlined recursively, because the
resulting tables get too wide with the current template.
This commit simplifies the exports.js plugin so it only relies
on the stability notes to generate the documentation, which
completely decouples it from the exportable API.
As a rule of thumb, whenever something has an 'api' annotation,
it should also have a 'stability' annotation. A more verbose
documentation of ol3 specific annotation usage is available in
the new 'apidoc/readme.md' file.
This commit also modifies all source files to implement these
usage suggestions.
